The Waldseemuller Map of 1507 introduced an astonishing collection of cartological firsts. It was the first map to show the New World as a separate continent, alongside Europe, Africa and Asia - and the first on which the word 'America' appears. It was the first map to suggest the existence of the Pacific. It was, in short, the first map to depict the whole world as we know it today.Beautiful, fascinating and revealing, it arrived on the scene as Europeans were moving out of the Middle Ages and into the Renaissance, thanks to a tiny group of European mapmakers who pieced together ideas going back to the ancients and through Marco Polo to Vespucci. In The Fourth Part of the World, Toby Lester charts the amazing and colourful history of this map, whose profound influence has been neglected for centuries and which changed the world-view of all humankind.